ISO standard · reference card
ISO 17636-2: scope of digital radiographic testing
Does ISO 17636-2 apply to your radiography setup? Scope decision flow for the digital-detector radiographic testing standard, the film-based counterpart, and the records that support an NDT report.
- Designation
- ISO 17636-2
- Issued by
- ISO
- Title
- Non-destructive testing of welds — Radiographic testing — Part 2: X- and gamma-ray techniques with digital detectors
- Edition
- Confirm the edition your certification body works to.
ISO 17636-2 governs how a radiograph is made with a digital detector, not what it is allowed to show. Technique class, source selection and image-quality demonstration sit inside this part; the accept/reject call on an indication belongs to the application or quality-level standard the contract names.
The recurring confusion is between this part and ISO 17636-1: a digital workflow bought to replace film has to be requalified against the digital-detector requirements, not simply assumed equivalent because the joint and the source have not changed. The second gap is scheduling radiography by convenience rather than by risk — a volumetric method finds internal porosity and lack of fusion that no amount of surface inspection will reveal, and skipping or thinning it on the wrong welds is where the value of the method is lost.
Therness equipment does not perform radiographic testing. It produces the per-weld thermal and process record that helps decide where radiography matters most, and ties that record to the same weld identifier the radiographic report references.
Scope: does it apply to your job?
Applies to
- Radiographic testing of fusion-welded joints in metallic materials using X-ray or gamma-ray sources with digital detectors
- Technique class selection (basic or improved) and the image-quality demonstration that supports it
- Butt and other fusion joints where a source/detector geometry permitted by the standard can be set up
Does not apply to
- Film-based radiography, which is covered by ISO 17636-1
- Setting the acceptance criteria for what the radiograph shows, which comes from an application or quality-level standard
- Other volumetric methods such as ultrasonic or phased-array testing
Applicability decision flow
| Question | If yes | If no |
|---|---|---|
| Is the detector digital — computed radiography or a digital detector array — rather than film? | ISO 17636-2 is the applicable part. | Film-based work follows ISO 17636-1 instead. |
| Does the contract or application standard specify a technique class? | Work to the class it names; the improved class demands more of the equipment and image quality than the basic class. | Agree the class with the client before testing — it is not the radiographer's default to choose alone. |
| Is the acceptance level for what the image shows already defined? | Apply it once the radiograph is made; ISO 17636-2 governs the technique, not the accept/reject decision. | An application or quality-level standard has to supply it first, commonly ISO 5817 for fusion-welded steel joints. |
| Is the joint accessible from only one side? | Only a double-wall technique is possible; source and detector sit on the same side and the radiation crosses both walls. | Single-wall technique is preferred where both sides are reachable; it gives the most source and detector geometry options. |
What proves conformity, and what only supports it
Conformity is decided by inspection and testing against the criteria the standard and the contract set. The records below are evidence that the process was held where it was qualified; they support an inspection result, they never replace one.
| Requirement | Record produced | Source |
|---|---|---|
| Targeting radiographic effort at the welds most likely to need it | Continuous thermal anomaly flag per weld, generated ahead of the radiography schedule | HeatCam IR-C |
| A production record to accompany the radiographic report | Weld identifier, operator, timestamp and process parameters exported per weld | WeldTrace |
| A searchable link between a radiograph and the production conditions that made the joint | Per-weld evidence set joined to the same weld identifier the NDT report references | HeatCore AI |
Evidence the process, not just the paperwork
Therness records what the machine actually delivered on every weld — parameters, thermal signature and a per-weld trail — so a conformity argument rests on measurements instead of recollection.
